“We saw the thief grab the map but he was away and out the window before anyone had a moment to react. The chase after him went from rooftop to rooftop and even across Thunder Lane before we forced him down into a courtyard where Ehrik repeatedly dunked his head into a small fountain to try to find out where along the way he had managed to ditch the map.”

After a few too many games of Assassin’s Creed, or just lovely flashbacks to the starter adventure scene in the original Warhammer Fantasy RPG chasing Bertoldo Vasari across the rooftops of Nuln, sooner or later you are going to want to run a rooftop chase scene.

This map assumes a society and climate where moderately pitched roofing is the norm – with an average of about a 30 degree slope. Dashing on a 30 degree slope can be difficult, might take a few rolls. And the general rule of thumb for a snowy climate is that roofs slope up six to nine inches for every foot they cover, so assume that the peak of a roof is 1/4 to 1/3 the total width of the building above the level of the edge of the roof. So on a 20 foot wide building, the roof slopes up to 5-7 feet in the centre. This allows for easy transfer from a 3 story building to a 4 story building as long as the peak of the lower building approaches the side of the taller.

The buildings have numbers on them to indicate how many stories above street level they reach so you can figure out where jumping and climbing will come into play, and on the blog post there is also a sample routing along the rooftops for a would-be thief to attempt an escape before the party almost inevitably runs them down.